This project is designed as a methodical investigation into the mechanisms by which the opiate drugs produce their motility effects on the gastrointestinal tract. The roles of adrenergic amines, especially dopamine; cyclic nucleotides; prostaglandins; and gamma-amino butyric acid in intestinal responses to opiates will be performed. Morphine, heroin and non-narcotic opiate-like drugs will be investigated. BIBLIOGRAPHIC REFERENCES: T.F. Burks and M.N. Grubb: 5-Hydroxytryptamine and cyclic AMP in intestinal stimulatory responses to morphine. Adv. Cyclic Nucleotide Res. 5: 840, 1975. T.F. Burks and M.N. Grubb: The mediator of morphine intestinal stimulatory actions. Sixth Intl. Cong. Pharmacol., 1975.